1. Field of the Invention
This invention relates to pile products and in particular to molded pile products.
2. Description of the Prior Art
As shown in Robert M. Conklin U.S. Pat. No. 3,804,617, owned by the assignee hereof, an improved synthetic resin pile product may be formed by a molding operation wherein the pile fibers extend from a base portion. The pile product may be so formed by means of a mold provided with a plurality of relatively small cross section, high aspect ratio (the ratio of the length to cross section) cavities. As indicated in said patent, the pile product may be formed of suitable polymeric material, such as polyvinyl chloride, polyethylene, polypropylene, and polyurethane.
As indicated in said Conklin patent, prior disclosures of the molding of pile products were presented in the applications of Tompkins and Moore entitled Molded Pile, filed Jan. 5, 1972, Ser. No. 215,623 and Roberts and Acciavatti entitled Process For Making Pile Materials and Pile Materials Produced Therefrom, filed Jan. 5, 1972, Ser. No. 215,557, now abandoned, and the issued U.S. Pat. Nos. 3,027,595, 3,141,051 and 3,317,633 to Unokichi Takai. As disclosed in the Takai U.S. Pat. No. 3,141,051, his suedelike material may be formed of vinyl plastic or other material, such as polyethylene, polypropylene, polyvinyl acetate, polystyrene, etc. In the Takai U.S. Pat. No. 3,317,644, he discloses the use of a polyvinyl chloride pile material.
Additional pertinent prior art would appear to be that disclosed in the U.S. Pat. Nos. 3,316,592, 3,632,842 and 3,655,497 of Norman Forrest. In U.S. Pat. No. 3,316,592, Forrest discloses forming pile material from vinyl and similar plastics. In U.S. Pat. No. 3,632,842, he discloses formation of synthetic suede from polyvinyl chloride. In U.S. Pat. No. 3,655,487, he teaches the formation of the synthetic suede from polyvinyl chloride resins or plastisols including all of the halo ethylene polymers of a certain type, listing numerous examples thereof.
One major problem with manufacturing molded pile products is to repeatedly remove the product from the mold without elongating or breaking the pile fibers. This problem becomes more acute as the pile fibers become longer and thinner. With known molding techniques it is believed impossible to repeatedly withdraw pile fibers from a mold where the aspect ratio (fiber length divided by fiber diameter) of the fiber is about 50 or greater.